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/*
* Copyright (c) 2014-2016 Advanced Micro Devices, Inc.
* Copyright (c) 2012 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2001-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "sim/process.hh"
#include <fcntl.h>
#include <unistd.h>
#include <array>
#include <climits>
#include <csignal>
#include <map>
#include <string>
#include <vector>
#include "base/intmath.hh"
#include "base/loader/object_file.hh"
#include "base/loader/symtab.hh"
#include "base/statistics.hh"
#include "cpu/thread_context.hh"
#include "mem/page_table.hh"
#include "mem/se_translating_port_proxy.hh"
#include "params/Process.hh"
#include "sim/emul_driver.hh"
#include "sim/fd_array.hh"
#include "sim/fd_entry.hh"
#include "sim/redirect_path.hh"
#include "sim/se_workload.hh"
#include "sim/syscall_desc.hh"
#include "sim/system.hh"
namespace gem5
{
namespace
{
typedef std::vector<Process::Loader *> LoaderList;
LoaderList &
process_loaders()
{
static LoaderList loaders;
return loaders;
}
} // anonymous namespace
Process::Loader::Loader()
{
process_loaders().emplace_back(this);
}
Process *
Process::tryLoaders(const ProcessParams &params,
loader::ObjectFile *obj_file)
{
for (auto &loader_it : process_loaders()) {
Process *p = loader_it->load(params, obj_file);
if (p)
return p;
}
return nullptr;
}
static std::string
normalize(const std::string& directory)
{
if (directory.back() != '/')
return directory + '/';
return directory;
}
Process::Process(const ProcessParams &params, EmulationPageTable *pTable,
loader::ObjectFile *obj_file)
: SimObject(params), system(params.system),
seWorkload(dynamic_cast<SEWorkload *>(system->workload)),
useArchPT(params.useArchPT),
kvmInSE(params.kvmInSE),
useForClone(false),
pTable(pTable),
objFile(obj_file),
argv(params.cmd), envp(params.env),
executable(params.executable == "" ? params.cmd[0] : params.executable),
tgtCwd(normalize(params.cwd)),
hostCwd(checkPathRedirect(tgtCwd)),
release(params.release),
_uid(params.uid), _euid(params.euid),
_gid(params.gid), _egid(params.egid),
_pid(params.pid), _ppid(params.ppid),
_pgid(params.pgid), drivers(params.drivers),
fds(std::make_shared<FDArray>(
params.input, params.output, params.errout)),
childClearTID(0),
ADD_STAT(numSyscalls, statistics::units::Count::get(),
"Number of system calls")
{
fatal_if(!seWorkload, "Couldn't find appropriate workload object.");
fatal_if(_pid >= System::maxPID, "_pid is too large: %d", _pid);
auto ret_pair = system->PIDs.emplace(_pid);
fatal_if(!ret_pair.second, "_pid %d is already used", _pid);
/**
* Linux bundles together processes into this concept called a thread
* group. The thread group is responsible for recording which processes
* behave as threads within a process context. The thread group leader
* is the process who's tgid is equal to its pid. Other processes which
* belong to the thread group, but do not lead the thread group, are
* treated as child threads. These threads are created by the clone system
* call with options specified to create threads (differing from the
* options used to implement a fork). By default, set up the tgid/pid
* with a new, equivalent value. If CLONE_THREAD is specified, patch
* the tgid value with the old process' value.
*/
_tgid = params.pid;
exitGroup = new bool();
sigchld = new bool();
image = objFile->buildImage();
if (loader::debugSymbolTable.empty())
loader::debugSymbolTable = objFile->symtab();
}
void
Process::clone(ThreadContext *otc, ThreadContext *ntc,
Process *np, RegVal flags)
{
#ifndef CLONE_VM
#define CLONE_VM 0
#endif
#ifndef CLONE_FILES
#define CLONE_FILES 0
#endif
#ifndef CLONE_THREAD
#define CLONE_THREAD 0
#endif
#ifndef CLONE_VFORK
#define CLONE_VFORK 0
#endif
if (CLONE_VM & flags) {
/**
* Share the process memory address space between the new process
* and the old process. Changes in one will be visible in the other
* due to the pointer use.
*/
delete np->pTable;
np->pTable = pTable;
np->memState = memState;
} else {
/**
* Duplicate the process memory address space. The state needs to be
* copied over (rather than using pointers to share everything).
*/
typedef std::vector<std::pair<Addr,Addr>> MapVec;
MapVec mappings;
pTable->getMappings(&mappings);
for (auto map : mappings) {
Addr paddr, vaddr = map.first;
bool alloc_page = !(np->pTable->translate(vaddr, paddr));
np->replicatePage(vaddr, paddr, otc, ntc, alloc_page);
}
*np->memState = *memState;
}
if (CLONE_FILES & flags) {
/**
* The parent and child file descriptors are shared because the
* two FDArray pointers are pointing to the same FDArray. Opening
* and closing file descriptors will be visible to both processes.
*/
np->fds = fds;
} else {
/**
* Copy the file descriptors from the old process into the new
* child process. The file descriptors entry can be opened and
* closed independently of the other process being considered. The
* host file descriptors are also dup'd so that the flags for the
* host file descriptor is independent of the other process.
*/
std::shared_ptr<FDArray> nfds = np->fds;
for (int tgt_fd = 0; tgt_fd < fds->getSize(); tgt_fd++) {
std::shared_ptr<FDEntry> this_fde = (*fds)[tgt_fd];
if (!this_fde) {
nfds->setFDEntry(tgt_fd, nullptr);
continue;
}
nfds->setFDEntry(tgt_fd, this_fde->clone());
auto this_hbfd = std::dynamic_pointer_cast<HBFDEntry>(this_fde);
if (!this_hbfd)
continue;
int this_sim_fd = this_hbfd->getSimFD();
if (this_sim_fd <= 2)
continue;
int np_sim_fd = dup(this_sim_fd);
assert(np_sim_fd != -1);
auto nhbfd = std::dynamic_pointer_cast<HBFDEntry>((*nfds)[tgt_fd]);
nhbfd->setSimFD(np_sim_fd);
}
}
if (CLONE_THREAD & flags) {
np->_tgid = _tgid;
delete np->exitGroup;
np->exitGroup = exitGroup;
}
if (CLONE_VFORK & flags) {
np->vforkContexts.push_back(otc->contextId());
}
np->argv.insert(np->argv.end(), argv.begin(), argv.end());
np->envp.insert(np->envp.end(), envp.begin(), envp.end());
}
void
Process::revokeThreadContext(int context_id)
{
std::vector<ContextID>::iterator it;
for (it = contextIds.begin(); it != contextIds.end(); it++) {
if (*it == context_id) {
contextIds.erase(it);
return;
}
}
warn("Unable to find thread context to revoke");
}
void
Process::init()
{
// Patch the ld_bias for dynamic executables.
updateBias();
if (objFile->getInterpreter())
interpImage = objFile->getInterpreter()->buildImage();
}
void
Process::initState()
{
if (contextIds.empty())
fatal("Process %s is not associated with any HW contexts!\n", name());
// first thread context for this process... initialize & enable
ThreadContext *tc = system->threads[contextIds[0]];
// mark this context as active so it will start ticking.
tc->activate();
pTable->initState();
initVirtMem.reset(new SETranslatingPortProxy(
tc, SETranslatingPortProxy::Always));
// load object file into target memory
image.write(*initVirtMem);
interpImage.write(*initVirtMem);
}
DrainState
Process::drain()
{
fds->updateFileOffsets();
return DrainState::Drained;
}
void
Process::allocateMem(Addr vaddr, int64_t size, bool clobber)
{
const auto page_size = pTable->pageSize();
const Addr page_addr = roundDown(vaddr, page_size);
// Check if the page has been mapped by other cores if not to clobber.
// When running multithreaded programs in SE-mode with DerivO3CPU model,
// there are cases where two or more cores have page faults on the same
// page in nearby ticks. When the cores try to handle the faults at the
// commit stage (also in nearby ticks/cycles), the first core will ask for
// a physical page frame to map with the virtual page. Other cores can
// return if the page has been mapped and `!clobber`.
if (!clobber) {
const EmulationPageTable::Entry *pte = pTable->lookup(page_addr);
if (pte) {
warn("Process::allocateMem: addr %#x already mapped\n", vaddr);
return;
}
}
const int npages = divCeil(size, page_size);
const Addr paddr = seWorkload->allocPhysPages(npages);
const Addr pages_size = npages * page_size;
pTable->map(page_addr, paddr, pages_size,
clobber ? EmulationPageTable::Clobber :
EmulationPageTable::MappingFlags(0));
}
void
Process::replicatePage(Addr vaddr, Addr new_paddr, ThreadContext *old_tc,
ThreadContext *new_tc, bool allocate_page)
{
if (allocate_page)
new_paddr = seWorkload->allocPhysPages(1);
// Read from old physical page.
uint8_t buf_p[pTable->pageSize()];
SETranslatingPortProxy(old_tc).readBlob(vaddr, buf_p, sizeof(buf_p));
// Create new mapping in process address space by clobbering existing
// mapping (if any existed) and then write to the new physical page.
bool clobber = true;
pTable->map(vaddr, new_paddr, sizeof(buf_p), clobber);
SETranslatingPortProxy(new_tc).writeBlob(vaddr, buf_p, sizeof(buf_p));
}
bool
Process::fixupFault(Addr vaddr)
{
return memState->fixupFault(vaddr);
}
void
Process::serialize(CheckpointOut &cp) const
{
memState->serialize(cp);
pTable->serialize(cp);
fds->serialize(cp);
/**
* Checkpoints for pipes, device drivers or sockets currently
* do not work. Need to come back and fix them at a later date.
*/
warn("Checkpoints for pipes, device drivers and sockets do not work.");
}
void
Process::unserialize(CheckpointIn &cp)
{
memState->unserialize(cp);
pTable->unserialize(cp);
fds->unserialize(cp);
/**
* Checkpoints for pipes, device drivers or sockets currently
* do not work. Need to come back and fix them at a later date.
*/
warn("Checkpoints for pipes, device drivers and sockets do not work.");
// The above returns a bool so that you could do something if you don't
// find the param in the checkpoint if you wanted to, like set a default
// but in this case we'll just stick with the instantiated value if not
// found.
}
bool
Process::map(Addr vaddr, Addr paddr, int size, bool cacheable)
{
pTable->map(vaddr, paddr, size,
cacheable ? EmulationPageTable::MappingFlags(0) :
EmulationPageTable::Uncacheable);
return true;
}
EmulatedDriver *
Process::findDriver(std::string filename)
{
for (EmulatedDriver *d : drivers) {
if (d->match(filename))
return d;
}
return nullptr;
}
std::string
Process::checkPathRedirect(const std::string &filename)
{
// If the input parameter contains a relative path, convert it.
// The target version of the current working directory is fine since
// we immediately convert it using redirect paths into a host version.
auto abs_path = absolutePath(filename, false);
for (auto path : system->redirectPaths) {
// Search through the redirect paths to see if a starting substring of
// our path falls into any buckets which need to redirected.
if (startswith(abs_path, path->appPath())) {
std::string tail = abs_path.substr(path->appPath().size());
// If this path needs to be redirected, search through a list
// of targets to see if we can match a valid file (or directory).
for (auto host_path : path->hostPaths()) {
if (access((host_path + tail).c_str(), R_OK) == 0) {
// Return the valid match.
return host_path + tail;
}
}
// The path needs to be redirected, but the file or directory
// does not exist on the host filesystem. Return the first
// host path as a default.
return path->hostPaths()[0] + tail;
}
}
// The path does not need to be redirected.
return abs_path;
}
void
Process::updateBias()
{
auto *interp = objFile->getInterpreter();
if (!interp || !interp->relocatable())
return;
// Determine how large the interpreters footprint will be in the process
// address space.
Addr interp_mapsize = roundUp(interp->mapSize(), pTable->pageSize());
// We are allocating the memory area; set the bias to the lowest address
// in the allocated memory region.
Addr mmap_end = memState->getMmapEnd();
Addr ld_bias = mmapGrowsDown() ? mmap_end - interp_mapsize : mmap_end;
// Adjust the process mmap area to give the interpreter room; the real
// execve system call would just invoke the kernel's internal mmap
// functions to make these adjustments.
mmap_end = mmapGrowsDown() ? ld_bias : mmap_end + interp_mapsize;
memState->setMmapEnd(mmap_end);
interp->updateBias(ld_bias);
}
loader::ObjectFile *
Process::getInterpreter()
{
return objFile->getInterpreter();
}
Addr
Process::getBias()
{
auto *interp = getInterpreter();
return interp ? interp->bias() : objFile->bias();
}
Addr
Process::getStartPC()
{
auto *interp = getInterpreter();
return interp ? interp->entryPoint() : objFile->entryPoint();
}
std::string
Process::absolutePath(const std::string &filename, bool host_filesystem)
{
if (filename.empty() || startswith(filename, "/"))
return filename;
// Construct the absolute path given the current working directory for
// either the host filesystem or target filesystem. The distinction only
// matters if filesystem redirection is utilized in the simulation.
auto path_base = std::string();
if (host_filesystem) {
path_base = hostCwd;
assert(!hostCwd.empty());
} else {
path_base = tgtCwd;
assert(!tgtCwd.empty());
}
// Add a trailing '/' if the current working directory did not have one.
normalize(path_base);
// Append the filename onto the current working path.
auto absolute_path = path_base + filename;
return absolute_path;
}
Process *
ProcessParams::create() const
{
// If not specified, set the executable parameter equal to the
// simulated system's zeroth command line parameter
const std::string &exec = (executable == "") ? cmd[0] : executable;
auto *obj_file = loader::createObjectFile(exec);
fatal_if(!obj_file, "Cannot load object file %s.", exec);
Process *process = Process::tryLoaders(*this, obj_file);
fatal_if(!process, "Unknown error creating process object.");
return process;
}
} // namespace gem5